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61.
The authors report a case of acute abdomen in the third trimester of pregnancy as observed at the II Obstetrics and Gynecologic Department of Florence University. Emphasis is laid on the frequent abnormality of the symptomatology and therefore the difficult of early diagnosis. The conclusion is reached that a greater semeiologic accuracy on behalf of the specialist as well as memorization of the several clinical charts responsible for such pathology, allow an earlier diagnosis with consequent improvement of maternal and fetal prognosis.  相似文献   
62.
Research on achievement goal orientation in sport has relied primarily on traditional statistical methodology to examine group mean differences. Unfortunately, examination of the measurement model is generally ignored prior to means testing. This study reports an application of structural equation modeling (SEM) in testing measurement invariance and latent mean structure of the Task and Ego Orientation in Sport Questionnaire (TEOSQ; Duda & Nicholls, 1989) using male and female college students. A confirmatory factor analysis for testing invariance revealed invariant measurement properties and factor structures across gender, indicating that task and ego orientation are similarly conceptualized by male and female students. Subsequent testing of latent mean structures, however, showed significant gender differences with respect to ego orientation, but no difference in task orientation. The SEM procedures used in the present study demonstrate additional construct validity and internal consistency reliability for the TEOSQ and, by confirming its factor structure, provide a sound psychometric basis for its continued use in substantive studies focusing on the comparison of achievement goal orientation across gender.  相似文献   
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64.
A small array of antimicrobial peptides comprising three cysteine-terminated natural sequences covalently immobilized to pendant surface maleimide groups are used to bind and successfully discriminate five types of lipopolysaccharide (LPS) molecules. Using surface plasmon resonance, LPSs isolated from four strains of Escherichia coli and one strain of Pseudomonas aeruginosa yield distinct binding profiles to the three immobilized peptides. Linear discriminant analysis generated 100% training set and 80% validation set classification success for the 40 samples evaluated. This work demonstrates the discriminatory binding capabilities of immobilized antimicrobial peptides toward LPS molecules and alludes to their use as probes in pathogen sensing devices potentially superior to the current state-of-the-art.  相似文献   
65.
A method is reported for the controlled synthesis of device‐grade semiconducting polymers, utilizing a droplet‐based microfluidic reactor. Using poly(3‐hexylthiophene) (P3HT) as a test material, the reactor is shown to provide a controlled and stable environment for polymer synthesis, enabling control of molecular weight via tuning of flow conditions, reagent composition or temperature. Molecular weights of up to 92 000 Da are readily attainable, without leakage or reactor fouling. The method avoids the usual deterioration in materials quality that occurs when conventional batch syntheses are scaled from the sub‐gram level to higher quantities, with a prototype five‐channel reactor producing material of consistent molecular weight distribution and high regioregularity (>98%) at a rate of ≈60 g/day. The droplet‐synthesized P3HT compares favorably with commercial material in terms of absorption spectrum, polydispersity, regioregularity, and crystallinity, yielding power conversion efficiencies of up to 4% in bulk heterojunction solar cells with [6,6]‐phenyl‐C61‐butyric acid methyl ester.  相似文献   
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67.
This paper discusses how to improve the position precision of a semi-closed loop servo system. A support vector regression algorithm is chosen to model and predict position error. The predicted error is then fed back to the input entry to compensate the error. Fuzzy PID control is introduced to adjust the controlling rule of the PID controller in the semi-closed loop servo system so as to improve the dynamic response characteristics of the servo system and reach a high degree of position precision. A case study is implemented. The simulation and experimental results show that combining the improved fuzzy control with predicted position error feedback ensures a high degree of position precision and a high degree of dynamic response characteristics.  相似文献   
68.
Recently, we presented the tribological evaluation of self-lubricating sintered steels produced by taking advantage of the powder injection molding process, the recently introduced plasma-assisted debinding and sintering process, and the in situ formation of solid lubricant particles. This new processing route promotes the in situ generation of nanostructured turbostratic graphite particles during silicon carbide dissociation. In this work, we present the influence of surface finishing on the tribological behavior of self-lubricating composites sintered at 1150°C with (3 and 5 wt%) and without SiC additions. We discuss the effects of the surface topography (Ra) on the friction coefficient and wear rates of specimens and counterbodies. The tribological behavior was analyzed using linear reciprocating sliding tests (constant load of 7 N, 60-min duration). It was shown that the reduction in surface roughness increased both the friction coefficients and wear rates of specimens and counterbodies, probably due to plastic deformation and consequent graphite reservoir sealing. Chemical analyses of the wear scars using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis showed a tribolayer that was composed predominantly of carbon and oxygen. Analyses of the wear scars showed traces of plastic deformation on both samples and counterbodies and the predominance of abrasion as the main wear mechanism.  相似文献   
69.
The Digital Radio Mondiale (DRM) system broadcasts audio in the frequency band below 174 MHz  and . In this experiment in urban areas in Brazil, a hybrid signal composed of an analog AM signal and a digital DRM30 signal, with the same content, were broadcasted in diurnal and nocturnal transmissions. This paper describes the experimental setup, which employs the spectral shaping technique in simulcast transmission [14], and presents some results of medium wave propagation measurements campaigns that are being carried out in Brazil. The experiment is part of a series of field trials that are being conducted by the Brazilian Government which includes campaigns at MW, HF and VHF frequency bands.  相似文献   
70.
Entrepreneurial orientation (EO) is a strategic posture of an organization, and it is related to basic policies and practices for the development of entrepreneurial actions looking for creating competitive advantages. This study develops and tests a model of the relationship between entrepreneurial orientation and project success in Brazilian context. As quantitative research, a survey was used to collect data. A sample of 100 valid answers from project practitioners was treated through the structural equation modeling method. As research implications, the main result points out the positive correlation between the entrepreneurial orientation and the project success, contributing to the development of this research subject and helping to minimize the gap in the literature that addresses the relationship between project success and EO. In practical terms, understanding that innovativeness, risk taking, proactiveness, autonomy and competitive aggressiveness (the dimensions of the EO) can contribute to project success and can also indirectly impact on organizational performance, could help organizations get competitive advantage when developing correlate factors. Finally, the results suggest that practices of project management can be aligned to the firm's entrepreneurial orientation to enable firms to attain better results in their projects and generate a competitive advantage. On other hand, given the proportion of the impact of EO on project success (20.3%) identified in this study, it is critical that project management professionals expand their horizon to recognize other factors that affect project success.  相似文献   
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